Greenhouse screen
AssigneeAB Ludvig Svensson
InventorsPer Holgerson, Sara Widén
Life of this patent
Estimating the term…
Abstract
A greenhouse screen is described with strips of film material that are interconnected by a yarn system of transverse threads and longitudinal threads by means of knitting, warp-knitting or weaving process to form a continuous product is disclosed. At least some of the strips include a film material in the form of a single- or multilayer polyethylene film having a thickness of 10-70 micrometers. Said film has at least 2-4 wt.-% SiO2 particles having a D50 of 2-10 micrometers. The film is advantageously used as a screen providing light scattering properties particularly suited for greenhouse applications.
Claims22
A greenhouse screen comprising strips (11) of film material that are interconnected by a yarn system of transverse threads (12, 14, 18) and longitudinal threads (13a, 13b;
- 15;
- 19) by means of knitting, warp-knitting or weaving process to form a continuous product, characterized in that at least some of the strips (11) comprise a film in the form of a single- or multilayer polyethylene film with a thickness of 10-70 micrometers, said film comprising at least 1.7 wt.-% and a maximum of 4.5 wt.-% SiO2 particles having a D50 of 2-10 micrometers.
The greenhouse screen according to any one of the preceding claims, characterized in that said film comprises 2.0-4.2 wt.-%, such as 2.5-4.0 wt.-% of SiO2 by weight, based on the total weight of the film.
The greenhouse screen according to any one of the preceding claims, characterized in that said SiO2 particles have a D50 value of 3-9 micrometers, such as a D50 value of 4-8 micrometers, such as a D50 value of 5-7 micrometers.
The greenhouse screen according to any one of the preceding claims, characterized in that said film has a transparency of at least 70%, such as at least 75%, 80%, 85%, 86%, 87%, 88%, 90%, 91%, 92%, 93% or higher.
The greenhouse screen according to any one of the preceding claims, characterized in that said film has a haze should be 50-75%, such as 54-70%, such as 57-67%.
The greenhouse screen according to any one of the preceding claims, characterized in that said film has a spreading factor (SF) is between 1.5 and 7, such as between 1.8 and 6, such as between 1.9 and 5, such as between 2 and 4.
The greenhouse screen according to any one of the preceding claims, characterized in that said film has a total thickness of 15-50 micrometers, such as 20-40 micrometers, such as 20-35 micrometers.
The greenhouse screen according to any one of the preceding claims, characterized in that said film is selected from the group consisting of UV absorbers, excited-state quenchers, or Hindered-Amine Light Stabilizers (HALS).
The greenhouse screen according to any one of the preceding claims, characterized in that the film is stretched before it is cut into strips.
The greenhouse screen according to any one of the preceding claims, characterized in that the film is stretched after it has been cut into strips.
The greenhouse screen according to any one of the preceding claims, characterized in that the film is uniaxially stretched to a ratio of 1:3 to 1:10, such as from 1:4 to 1:8, such as from 1:5 to 1:7.
Dependencies are inferred from the claim text.